That's true only if you reduce "progress" to "GDP growth". As much as economists see prices of goods (e.g. houses, transportation, iPhones) falling as a bad thing, it's actually the true indicator of progress.
Aggregate deflation is not a positive for an economy. It's nice that some sectors are more accessile than previous centuries, esp. food and clothing, but that doesn't mean that deflation in every sector indicates forward momentum.
IIRC, deflation would be caused by a very fearful and therefore finacially conservative population.
